1. Field of Invention
The present invention relates to a drive gear unit for vertical blind systems.
More particularly, the invention relates to a drive gear unit for tilting vanes or slats of a vertical blind system for regulating inflow of sun rays and/or light into a room or other chamber.
2. Description of Related Prior Art
Various types of drive gear units for vertical blind systems are known.
Some of these systems are complicated and do not operate effectively.
Basically two types of drive gear units are known: The one type involves a worm gear drive, and the other a bevel gear drive.
Worm gear drives for vertical blind systems are for example disclosed in U.S. Pat. No. 5,630,457 (Chou), U.S. Pat. No. 3,134,428 (Kehrer et al), U.S. Pat. No. 3,343,588 (Cayton), U.S. Pat. No. 3,605,852 (Vecchlarelli et al).
Bevel gear drives for vertical blind systems are for example described in U.S. Pat. No. 4,316,493 (Arena), U.S. Pat. No. 5,547,007 (Grutzner), U.S. Pat. No. 3,269,453 (Vecchiarelli et al).
The bevel or mitre gear arrangements or the worm gear drives have to be very accurately produced to operate efficiently and therefore the tooling and production costs are expensive. Furthermore the assembly time is time consuming and costly.
It therefore is a primary object of the invention to suggest a drive gear unit for vertical blind systems, which will provide an improvement to known systems.
In accordance with the invention, a drive gear unit for tilting vertically orientated slats of a vertical blind system, includes
a) a frame; PA1 b) connection means for connecting the frame to a tubular support rail for a vertical blind system including a vertical blind drive rod and rotatable, vertically orientated slats; PA1 c) a wand drive member having a shaft and a first spur gear wheel provided on the shaft and being rotatably mounted on the frame so that the shaft has an end extending out of the frame for operative connection to a wand and the first spur gear wheel being located inside the frame, the first spur gear having teeth which extend radially outwardly from a central hub; PA1 d) a rod locating member associated with the frame and having a passage for locatingly receiving a vertical blind drive rod; PA1 e) a rod drive member having a rod connecting part adapted to be operatively joined to a rod vertical blind drive rod located by way of the rod locating member, and further having a second spur gear wheel joined to the rod connecting part, the second spur gear wheel having teeth which extend radially outwardly from a central hub; and PA1 f) the first spur gear wheel and the second spur gear wheel being in operative mesh.
The first spur gear wheel may have a smaller diameter than the second spur gear wheel.
The first spur gear wheel may have five circumferentially distributed teeth.
The second spur gear wheel may have nine circumferentially distributed teeth.
The teeth of the spur gear wheels may have substantially parallel sides and a curved free end.
The first spur gear wheel may have a rotational axis which is substantially at right angles to the rotational axis of the second spur gear wheel. However, the rotational axes of the first and second spur gear wheels may also be provided at an angle less than or more than 90.degree., e.g. at 75.degree. or 105.degree., wherever required.
The shaft of the wand drive member may have an aperture for receiving a wand hook.
The rod connecting part of the rod drive member may include a hollow cylinder having a number of internal circumferentially distributed elongated ridges for fitting into corresponding elongated grooves of a vertical blind drive rod.
The frame may have a rear wall having a round protrusion and the second spur gear wheel has a circular recess rotatably receiving the round protrusion.
The invention also extends to a vertical blind system including a drive gear unit as set out herein.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawing and descriptive matter in which there are illustrated and described preferred embodiments of the invention.